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Common-emitter gives more voltage gain because a common-collector amplifier has a voltage gain of 1. But a common-collector can have a power gain because the input impedance is much more than the output impedance.
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Why output of common emitter amplifier is inverted?
In a common emitter amplifier, the base-emitter current causes a corresponding collector-emitter current, in the ratio of hFe (beta gain) or collector resistance over emitter resistance, which ever is less. Since this ratio is usually greater than one, the differential collector current is greater than the differential base current. This results in amplification of the base signal. As you increase the base-emitter current, the collector-emitter current also increases. This results in the collector being pulled towards the emitter, with the result that the differential collector voltage decreases. This results in inversion of the base signal.
What is transistor action?
The transistor has three regions, emitter,base and collector. The base is much thinner than the emitter while the collector is wider than both. However for the sake of convenience the emitter and collector are usually shown to be of equal size. The transistor has two pn junctions that means it is like two diodes. The junction between emitter and base may be called emitter-base diode or simply the emitter diode.The junction between base and collector may be called collector-base diode or simply collector diode. The emitter diode is always forward biased and the collector diode is always reverse biased.
Explain why the collector voltage is approximately zero when a transistor has a collector-emitter short?
The collector voltage is not necessarily approximately zero when a transistor has a collector-emitter short. It depends on whether or not there is an emitter resistor.A typical collector-emitter circuit has two resistors, one in the collector and one in the emitter. One or both of them might be zero, i.e. not present, depending on design requirements. The collector-emitter junction represents a third resistor, the value of which is dependent on base-emitter vs collector-emitter current ratios and hFe.If the collector-emitter junction is shorted, then this circuit degrades to a simple voltage divider, or single resistor, and the collector-emitter voltage differential will be approximately zero. Simply calculate the voltage based on the one or two resistances.Results could be different than calculated, if the resistors are small in camparision to the shorted impedance, and it could be different depending on the base to emitter or collector relationship in that fault state, though the latter case is usually negligible due to the relatively high resistances of the base bias circuit.
Why is the base current in a transistor so much less than the collector current?
as the base current is very small compared to the emitter current,the collector current is nearly equal to the emitter current..
Why collector is made larger than base and emitter in a transistor?
Collector has larger area than base and emitter because base collector is reverse biased, hence the current flow here due to the minority carriers and the large power dissipation takes place by the majority carriers, this power dissipated in the form of heat.. To cool the device from heat we made the larger area........
Why output of common emitter amplifier is inverted?
In a common emitter amplifier, the base-emitter current causes a corresponding collector-emitter current, in the ratio of hFe (beta gain) or collector resistance over emitter resistance, which ever is less. Since this ratio is usually greater than one, the differential collector current is greater than the differential base current. This results in amplification of the base signal. As you increase the base-emitter current, the collector-emitter current also increases. This results in the collector being pulled towards the emitter, with the result that the differential collector voltage decreases. This results in inversion of the base signal.
What will happen to voltage divider circuit if emitter resistance is greater than collector resistance?
The gain of a class A, common emitter BJT amplifier, a fairly standard configuration, is defined as collector resistance divided by emitter resistance, or as hFe, whichever is less. Assuming that we are operating in a linear mode, and hFe is not a limiting factor, then the emitter resistance being greater than the collector resistance simply means that the gain is less than one.
Why is collector current increased slowly with the increase of collector to emitter voltage of a common emitter?
The percentage of doping in emitter is higher than collector region.hence large current is flow to emitter than collector.
Why is collector current less than emitter current?
The percentage of doping in emitter is higher than collector region.hence large current is flow to emitter than collector.
Why is collector current slightly less than emitter?
The percentage of doping in emitter is higher than collector region.hence large current is flow to emitter than collector.
Why is collector slightly less than emitter?
some of emitter current goes out base instead of collector
What are the bias condition of the base emitter and base collector junction for a transistor to operate as a switch?
In order for a transistor to operate as a switch, the base-emitter current must be greater than the collector-emitter current divided by a factor of hFe. In this state, the transistor operates in saturated mode, fully turning on.
What are the bias conditions of the base emitter and base collector junction for a transistor to operate as a switch?
In order for a transistor to operate as a switch, the base-emitter current must be greater than the collector-emitter current divided by a factor of hFe. In this state, the transistor operates in saturated mode, fully turning on.
What is transistor action?
The transistor has three regions, emitter,base and collector. The base is much thinner than the emitter while the collector is wider than both. However for the sake of convenience the emitter and collector are usually shown to be of equal size. The transistor has two pn junctions that means it is like two diodes. The junction between emitter and base may be called emitter-base diode or simply the emitter diode.The junction between base and collector may be called collector-base diode or simply collector diode. The emitter diode is always forward biased and the collector diode is always reverse biased.
Why is junction capacitance of collector to base junction is lower than base to emitter junction?
The collector base depletion zone is wider than the emitter base depletion zone.
Which out of either the cccb or the ce configurations of a transistor is best and why?
The common emitter configuration works best because of the way the segments of transistors are biased, and the fact that there are more carriers in the collector than in the emitter.
Explain why the collector voltage is approximately zero when a transistor has a collector-emitter short?
The collector voltage is not necessarily approximately zero when a transistor has a collector-emitter short. It depends on whether or not there is an emitter resistor.A typical collector-emitter circuit has two resistors, one in the collector and one in the emitter. One or both of them might be zero, i.e. not present, depending on design requirements. The collector-emitter junction represents a third resistor, the value of which is dependent on base-emitter vs collector-emitter current ratios and hFe.If the collector-emitter junction is shorted, then this circuit degrades to a simple voltage divider, or single resistor, and the collector-emitter voltage differential will be approximately zero. Simply calculate the voltage based on the one or two resistances.Results could be different than calculated, if the resistors are small in camparision to the shorted impedance, and it could be different depending on the base to emitter or collector relationship in that fault state, though the latter case is usually negligible due to the relatively high resistances of the base bias circuit.
